1 From aaa675f07e781e248fcf169ce9a917b48bc2cc9b Mon Sep 17 00:00:00 2001
2 From: Brian Norris <computersforpeace@gmail.com>
3 Date: Fri, 28 Jul 2023 12:06:23 +0200
4 Subject: [PATCH 3/3] firmware: qcom: scm: fix SCM cold boot address
6 This effectively reverts upstream Linux commit 13e77747800e ("firmware:
7 qcom: scm: Use atomic SCM for cold boot"), because Google WiFi boot
8 firmwares don't support the atomic variant.
10 This fixes SMP support for Google WiFi.
12 Signed-off-by: Brian Norris <computersforpeace@gmail.com>
14 drivers/firmware/qcom_scm-legacy.c | 62 +++++++++++++++++++++++++-----
15 drivers/firmware/qcom_scm.c | 11 ++++++
16 2 files changed, 63 insertions(+), 10 deletions(-)
18 --- a/drivers/firmware/qcom_scm-legacy.c
19 +++ b/drivers/firmware/qcom_scm-legacy.c
21 #include <linux/arm-smccc.h>
22 #include <linux/dma-mapping.h>
24 +#include <asm/cacheflush.h>
25 +#include <asm/outercache.h>
29 static DEFINE_MUTEX(qcom_scm_lock);
30 @@ -117,6 +120,25 @@ static void __scm_legacy_do(const struct
31 } while (res->a0 == QCOM_SCM_INTERRUPTED);
34 +static void qcom_scm_inv_range(unsigned long start, unsigned long end)
36 + u32 cacheline_size, ctr;
38 + asm volatile("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
39 + cacheline_size = 4 << ((ctr >> 16) & 0xf);
41 + start = round_down(start, cacheline_size);
42 + end = round_up(end, cacheline_size);
43 + outer_inv_range(start, end);
44 + while (start < end) {
45 + asm ("mcr p15, 0, %0, c7, c6, 1" : : "r" (start)
47 + start += cacheline_size;
54 * scm_legacy_call() - Sends a command to the SCM and waits for the command to
56 @@ -163,10 +185,16 @@ int scm_legacy_call(struct device *dev,
58 rsp = scm_legacy_command_to_response(cmd);
60 - cmd_phys = dma_map_single(dev, cmd, alloc_len, DMA_TO_DEVICE);
61 - if (dma_mapping_error(dev, cmd_phys)) {
65 + cmd_phys = dma_map_single(dev, cmd, alloc_len, DMA_TO_DEVICE);
66 + if (dma_mapping_error(dev, cmd_phys)) {
71 + cmd_phys = virt_to_phys(cmd);
72 + __cpuc_flush_dcache_area(cmd, alloc_len);
73 + outer_flush_range(cmd_phys, cmd_phys + alloc_len);
77 @@ -182,13 +210,26 @@ int scm_legacy_call(struct device *dev,
81 - dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len,
82 - sizeof(*rsp), DMA_FROM_DEVICE);
84 + dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) +
85 + cmd_len, sizeof(*rsp),
88 + unsigned long start = (uintptr_t)cmd + sizeof(*cmd) +
90 + qcom_scm_inv_range(start, start + sizeof(*rsp));
92 } while (!rsp->is_complete);
94 - dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len +
95 - le32_to_cpu(rsp->buf_offset),
96 - resp_len, DMA_FROM_DEVICE);
98 + dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len +
99 + le32_to_cpu(rsp->buf_offset),
100 + resp_len, DMA_FROM_DEVICE);
102 + unsigned long start = (uintptr_t)cmd + sizeof(*cmd) + cmd_len +
103 + le32_to_cpu(rsp->buf_offset);
104 + qcom_scm_inv_range(start, start + resp_len);
108 res_buf = scm_legacy_get_response_buffer(rsp);
109 @@ -196,7 +237,8 @@ int scm_legacy_call(struct device *dev,
110 res->result[i] = le32_to_cpu(res_buf[i]);
113 - dma_unmap_single(dev, cmd_phys, alloc_len, DMA_TO_DEVICE);
115 + dma_unmap_single(dev, cmd_phys, alloc_len, DMA_TO_DEVICE);
119 --- a/drivers/firmware/qcom_scm.c
120 +++ b/drivers/firmware/qcom_scm.c
121 @@ -312,6 +312,17 @@ static int qcom_scm_set_boot_addr(void *
122 desc.args[0] = flags;
123 desc.args[1] = virt_to_phys(entry);
126 + * Factory firmware doesn't support the atomic variant. Non-atomic SCMs
127 + * require ugly DMA invalidation support that was dropped upstream a
128 + * while ago. For more info, see:
130 + * [RFC] qcom_scm: IPQ4019 firmware does not support atomic API?
131 + * https://lore.kernel.org/linux-arm-msm/20200913201608.GA3162100@bDebian/
133 + if (of_machine_is_compatible("google,wifi"))
134 + return qcom_scm_call(__scm ? __scm->dev : NULL, &desc, NULL);
136 return qcom_scm_call_atomic(__scm ? __scm->dev : NULL, &desc, NULL);