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[PATCH] MIPS: ath79: fix CPU/DDR frequency calculation for SRIF PLLs

To: Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH] MIPS: ath79: fix CPU/DDR frequency calculation for SRIF PLLs
From: Gabor Juhos <juhosg@openwrt.org>
Date: Sat, 8 Sep 2012 14:02:21 +0200
Cc: linux-mips@linux-mips.org, Gabor Juhos <juhosg@openwrt.org>, <stable@vger.kernel.org>
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Besides the CPU and DDR PLLs, the CPU and DDR frequencies
can be derived from other PLLs in the SRIF block on the
AR934x SoCs. The current code does not checks if the SRIF
PLLs are used and this can lead to incorrectly calculated
CPU/DDR frequencies.

Fix it by calculating the frequencies from SRIF PLLs if
those are used on a given board.

Cc: <stable@vger.kernel.org>
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
---
This depends on the following patch:
'MIPS: ath79: use correct fractional dividers for {CPU,DDR}_PLL on AR934x'
https://patchwork.linux-mips.org/patch/4305/

 arch/mips/ath79/clock.c                        |  109 ++++++++++++++++++------
 arch/mips/include/asm/mach-ath79/ar71xx_regs.h |   23 +++++
 2 files changed, 104 insertions(+), 28 deletions(-)

diff --git a/arch/mips/ath79/clock.c b/arch/mips/ath79/clock.c
index d272857..579f452 100644
--- a/arch/mips/ath79/clock.c
+++ b/arch/mips/ath79/clock.c
@@ -17,6 +17,8 @@
 #include <linux/err.h>
 #include <linux/clk.h>
 
+#include <asm/div64.h>
+
 #include <asm/mach-ath79/ath79.h>
 #include <asm/mach-ath79/ar71xx_regs.h>
 #include "common.h"
@@ -166,11 +168,34 @@ static void __init ar933x_clocks_init(void)
        ath79_uart_clk.rate = ath79_ref_clk.rate;
 }
 
+static u32 __init ar934x_get_pll_freq(u32 ref, u32 ref_div, u32 nint, u32 
nfrac,
+                                     u32 frac, u32 out_div)
+{
+       u64 t;
+       u32 ret;
+
+       t = ath79_ref_clk.rate;
+       t *= nint;
+       do_div(t, ref_div);
+       ret = t;
+
+       t = ath79_ref_clk.rate;
+       t *= nfrac;
+       do_div(t, ref_div * frac);
+       ret += t;
+
+       ret /= (1 << out_div);
+       return ret;
+}
+
 static void __init ar934x_clocks_init(void)
 {
-       u32 pll, out_div, ref_div, nint, frac, clk_ctrl, postdiv;
+       u32 pll, out_div, ref_div, nint, nfrac, frac, clk_ctrl, postdiv;
        u32 cpu_pll, ddr_pll;
        u32 bootstrap;
+       void __iomem *dpll_base;
+
+       dpll_base = ioremap(AR934X_SRIF_BASE, AR934X_SRIF_SIZE);
 
        bootstrap = ath79_reset_rr(AR934X_RESET_REG_BOOTSTRAP);
        if (bootstrap & AR934X_BOOTSTRAP_REF_CLK_40)
@@ -178,33 +203,59 @@ static void __init ar934x_clocks_init(void)
        else
                ath79_ref_clk.rate = 25 * 1000 * 1000;
 
-       pll = ath79_pll_rr(AR934X_PLL_CPU_CONFIG_REG);
-       out_div = (pll >> AR934X_PLL_CPU_CONFIG_OUTDIV_SHIFT) &
-                 AR934X_PLL_CPU_CONFIG_OUTDIV_MASK;
-       ref_div = (pll >> AR934X_PLL_CPU_CONFIG_REFDIV_SHIFT) &
-                 AR934X_PLL_CPU_CONFIG_REFDIV_MASK;
-       nint = (pll >> AR934X_PLL_CPU_CONFIG_NINT_SHIFT) &
-              AR934X_PLL_CPU_CONFIG_NINT_MASK;
-       frac = (pll >> AR934X_PLL_CPU_CONFIG_NFRAC_SHIFT) &
-              AR934X_PLL_CPU_CONFIG_NFRAC_MASK;
-
-       cpu_pll = nint * ath79_ref_clk.rate / ref_div;
-       cpu_pll += frac * ath79_ref_clk.rate / (ref_div * (1 << 6));
-       cpu_pll /= (1 << out_div);
-
-       pll = ath79_pll_rr(AR934X_PLL_DDR_CONFIG_REG);
-       out_div = (pll >> AR934X_PLL_DDR_CONFIG_OUTDIV_SHIFT) &
-                 AR934X_PLL_DDR_CONFIG_OUTDIV_MASK;
-       ref_div = (pll >> AR934X_PLL_DDR_CONFIG_REFDIV_SHIFT) &
-                 AR934X_PLL_DDR_CONFIG_REFDIV_MASK;
-       nint = (pll >> AR934X_PLL_DDR_CONFIG_NINT_SHIFT) &
-              AR934X_PLL_DDR_CONFIG_NINT_MASK;
-       frac = (pll >> AR934X_PLL_DDR_CONFIG_NFRAC_SHIFT) &
-              AR934X_PLL_DDR_CONFIG_NFRAC_MASK;
-
-       ddr_pll = nint * ath79_ref_clk.rate / ref_div;
-       ddr_pll += frac * ath79_ref_clk.rate / (ref_div * (1 << 10));
-       ddr_pll /= (1 << out_div);
+       pll = __raw_readl(dpll_base + AR934X_SRIF_CPU_DPLL2_REG);
+       if (pll & AR934X_SRIF_DPLL2_LOCAL_PLL) {
+               out_div = (pll >> AR934X_SRIF_DPLL2_OUTDIV_SHIFT) &
+                         AR934X_SRIF_DPLL2_OUTDIV_MASK;
+               pll = __raw_readl(dpll_base + AR934X_SRIF_CPU_DPLL1_REG);
+               nint = (pll >> AR934X_SRIF_DPLL1_NINT_SHIFT) &
+                      AR934X_SRIF_DPLL1_NINT_MASK;
+               nfrac = pll & AR934X_SRIF_DPLL1_NFRAC_MASK;
+               ref_div = (pll >> AR934X_SRIF_DPLL1_REFDIV_SHIFT) &
+                         AR934X_SRIF_DPLL1_REFDIV_MASK;
+               frac = 1 << 18;
+       } else {
+               pll = ath79_pll_rr(AR934X_PLL_CPU_CONFIG_REG);
+               out_div = (pll >> AR934X_PLL_CPU_CONFIG_OUTDIV_SHIFT) &
+                       AR934X_PLL_CPU_CONFIG_OUTDIV_MASK;
+               ref_div = (pll >> AR934X_PLL_CPU_CONFIG_REFDIV_SHIFT) &
+                         AR934X_PLL_CPU_CONFIG_REFDIV_MASK;
+               nint = (pll >> AR934X_PLL_CPU_CONFIG_NINT_SHIFT) &
+                      AR934X_PLL_CPU_CONFIG_NINT_MASK;
+               nfrac = (pll >> AR934X_PLL_CPU_CONFIG_NFRAC_SHIFT) &
+                       AR934X_PLL_CPU_CONFIG_NFRAC_MASK;
+               frac = 1 << 6;
+       }
+
+       cpu_pll = ar934x_get_pll_freq(ath79_ref_clk.rate, ref_div, nint,
+                                     nfrac, frac, out_div);
+
+       pll = __raw_readl(dpll_base + AR934X_SRIF_DDR_DPLL2_REG);
+       if (pll & AR934X_SRIF_DPLL2_LOCAL_PLL) {
+               out_div = (pll >> AR934X_SRIF_DPLL2_OUTDIV_SHIFT) &
+                         AR934X_SRIF_DPLL2_OUTDIV_MASK;
+               pll = __raw_readl(dpll_base + AR934X_SRIF_DDR_DPLL1_REG);
+               nint = (pll >> AR934X_SRIF_DPLL1_NINT_SHIFT) &
+                      AR934X_SRIF_DPLL1_NINT_MASK;
+               nfrac = pll & AR934X_SRIF_DPLL1_NFRAC_MASK;
+               ref_div = (pll >> AR934X_SRIF_DPLL1_REFDIV_SHIFT) &
+                         AR934X_SRIF_DPLL1_REFDIV_MASK;
+               frac = 1 << 18;
+       } else {
+               pll = ath79_pll_rr(AR934X_PLL_DDR_CONFIG_REG);
+               out_div = (pll >> AR934X_PLL_DDR_CONFIG_OUTDIV_SHIFT) &
+                         AR934X_PLL_DDR_CONFIG_OUTDIV_MASK;
+               ref_div = (pll >> AR934X_PLL_DDR_CONFIG_REFDIV_SHIFT) &
+                          AR934X_PLL_DDR_CONFIG_REFDIV_MASK;
+               nint = (pll >> AR934X_PLL_DDR_CONFIG_NINT_SHIFT) &
+                      AR934X_PLL_DDR_CONFIG_NINT_MASK;
+               nfrac = (pll >> AR934X_PLL_DDR_CONFIG_NFRAC_SHIFT) &
+                       AR934X_PLL_DDR_CONFIG_NFRAC_MASK;
+               frac = 1 << 10;
+       }
+
+       ddr_pll = ar934x_get_pll_freq(ath79_ref_clk.rate, ref_div, nint,
+                                     nfrac, frac, out_div);
 
        clk_ctrl = ath79_pll_rr(AR934X_PLL_CPU_DDR_CLK_CTRL_REG);
 
@@ -240,6 +291,8 @@ static void __init ar934x_clocks_init(void)
 
        ath79_wdt_clk.rate = ath79_ref_clk.rate;
        ath79_uart_clk.rate = ath79_ref_clk.rate;
+
+       iounmap(dpll_base);
 }
 
 void __init ath79_clocks_init(void)
diff --git a/arch/mips/include/asm/mach-ath79/ar71xx_regs.h 
b/arch/mips/include/asm/mach-ath79/ar71xx_regs.h
index 3ccae12..a5e0f17 100644
--- a/arch/mips/include/asm/mach-ath79/ar71xx_regs.h
+++ b/arch/mips/include/asm/mach-ath79/ar71xx_regs.h
@@ -65,6 +65,8 @@
 #define AR934X_WMAC_SIZE       0x20000
 #define AR934X_EHCI_BASE       0x1b000000
 #define AR934X_EHCI_SIZE       0x200
+#define AR934X_SRIF_BASE       (AR71XX_APB_BASE + 0x00116000)
+#define AR934X_SRIF_SIZE       0x1000
 
 /*
  * DDR_CTRL block
@@ -406,4 +408,25 @@
 #define AR933X_GPIO_COUNT              30
 #define AR934X_GPIO_COUNT              23
 
+/*
+ * SRIF block
+ */
+#define AR934X_SRIF_CPU_DPLL1_REG      0x1c0
+#define AR934X_SRIF_CPU_DPLL2_REG      0x1c4
+#define AR934X_SRIF_CPU_DPLL3_REG      0x1c8
+
+#define AR934X_SRIF_DDR_DPLL1_REG      0x240
+#define AR934X_SRIF_DDR_DPLL2_REG      0x244
+#define AR934X_SRIF_DDR_DPLL3_REG      0x248
+
+#define AR934X_SRIF_DPLL1_REFDIV_SHIFT 27
+#define AR934X_SRIF_DPLL1_REFDIV_MASK  0x1f
+#define AR934X_SRIF_DPLL1_NINT_SHIFT   18
+#define AR934X_SRIF_DPLL1_NINT_MASK    0x1ff
+#define AR934X_SRIF_DPLL1_NFRAC_MASK   0x0003ffff
+
+#define AR934X_SRIF_DPLL2_LOCAL_PLL    BIT(30)
+#define AR934X_SRIF_DPLL2_OUTDIV_SHIFT 13
+#define AR934X_SRIF_DPLL2_OUTDIV_MASK  0x7
+
 #endif /* __ASM_MACH_AR71XX_REGS_H */
-- 
1.7.10


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